Date of birth
Republic of Ireland
Irishman Mark re-joined the club in July 2016, having spent two seasons at Crawley between 2012-14.
The former Wolves and Bolton central defender joined Kilmarnock after his first spell with the Reds and was made club captain at Killie, although his second year at Rugby Park was disrupted when he broke his shoulder.
He returned to Reds in the summer of 2016 on a two-year contract and made 46 appearances in the 2016/17 season.